The overall objective of this application is to decrease preterm birth (PTB) in minority women. Mechanisms underlying preterm birth will be explicated by developing a prognostic model of PTB in African American (AA) women at 22-24 weeks, a period of periviability, and validating the model in Mexican American (MA) women. Additionally, in AA women, who are most at risk for early PTB (<32 weeks gestation), mechanisms underlying preterm labor and PTB will be explicated. As only 40-50 percent of preterm labor ends in PTB, understanding factors that differentiate preterm labor from PTB is vital in improving care of preterm labor and in preventing preterm birth. To meet the specific aims of this study we will: Specific Aim 1: In AA women experiencing uncomplicated pregnancies examine the predictive ability at 22-24 weeks gestation of stress (perceived stress, racism, CRH), depression, coping behaviors, immune function (vaginal cytokines), health behaviors (BMI and smoking), and infection (including Chlamydia, gonorrhea, and bacterial vaginosis), in differentiating those AA women who will deliver preterm, from those who will deliver at term, by building a prognostic model. 1a. Validate the prognostic model for preterm delivery that was developed in AA women in an external population of MA women. Specific Aim 2: In AA women experiencing early preterm labor (between 22-32 weeks gestation) examine the predictive ability of stress (perceived stress, racism, CRH), depression, coping behaviors, immune function (vaginal and cervical cytokines), infection (including Chlamydia, gonorrhea and bacterial vaginosis), and health behaviors (smoking, BMI, nutritional intake) in differentiating those AA who will deliver preterm from those who will deliver at term by building a prognostic model. Specific Aim 3: Examine the timing and contribution of mutable factors including stress (perceived stress and CRH), depression, coping behaviors, immune function (vaginal and cervical cytokines), infection ( including Chlamydia, gonorrhea and bacterial vaginosis), and health behaviors (smoking, BMI and nutritional intake) between the onset of preterm labor (or 22-24 weeks of gestation for women who do not experience preterm labor) to delivery outcome in three groups of AA women (those who: 1) labor and deliver prematurely, 2) labor prematurely but deliver at term and 3) experience only term labor and delivery). The information obtained from this study will provide knowledge about psychosocial, behavioral and physiologic factors that underlie preterm labor and preterm birth and is necessary to develop effective nursing interventions to improve birth outcomes in minority women. . PUBLIC HEALTH RELEVANCE Identifying factors that predict preterm birth early (22-24 weeks) in pregnancy is important in order to decrease preterm birth in minority women. Factors predicting preterm birth in African American women will be explicated by comparing them with factors predicting preterm birth in Mexican American women. Information about minority women most likely to labor prematurely but deliver at term and those most likely to experience preterm labor and delivery will be obtained in African American women, who are most at risk for early preterm birth, so that targeted interventions can be designed to improve the care of preterm labor and prevent preterm birth.